Re: [WIP] Add relminxid column to pg_class

Tom Lane wrote:

> I see a workaround though: it *is* OK for VACUUM FREEZE to set datminxid
> = FrozenXid if (1) it's been able to freeze all the tables and (2) it's
> running in a standalone backend. This rule would let us freeze
> template0 during initdb.
>
> There's still a question of where/when to worry about marking a database
> unfrozen. Perhaps a suitably cheap, conservative approximation would be
> to cause any new connection to a frozen database to immediately mark it
> unfrozen in pg_database. (I'm not sure if this works conveniently for
> initdb's processing though --- we might want to fudge a bit depending on
> whether we're running standalone.)

initdb never connects to template0, so I think it should work. We just
need to add an additional step to initdb to run the vacuum freeze.

What do you think of making vacuum a no-op on a table that has datminxid
= FrozenXid?

--
Alvaro Herrera http://www.CommandPrompt.com/
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